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Sexual selection and signalling in the lizard Platysaurus minorLewis, Belinda Ann 08 April 2008 (has links)
ABSTRACT
Sexual selection may influence aspects of male morphology associated with territoriality, female choice, aggression and contest success. Attributes that are most commonly selected for include body size, condition, weaponry, endurance and bright coloration. I investigated the relationships between morphology, use of space and home range quality, and access to females. Specifically, I examined the relationships between colour, body size and condition, and whether morphology could predict aggression or contest success. Colour spectral data were analyzed using both traditional measures of colour (hue, chroma, brightness) and principal components. Males with darker, more saturated chests, and more saturated throats, had larger home ranges. Home range quality, as determined by refuge number and prey availability, was associated with blue chests and blue throats and chests, respectively. Males with larger home ranges had higher numbers of associated females and spent more time courting females. Larger males in better condition had darker, more saturated chests. Males in better body condition were also more aggressive. There was a consistent trend for larger males to win more contests, but this relationship was only significant in analyses using traditional measures of colour.
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Stratégies de reproduction et de dispersion chez deux termites humivores de Guyane, Embiratermes neotenicus et Silvestritermes minutus (Termitidae, Syntermitinae) / Reproductive and dispersive strategies in two soil-feeding termites, Embiratermes neotenicus and Silvestritermes minutus (Termitidae, Syntermitinae)Fougeyrollas, Romain 16 December 2016 (has links)
Chez les insectes sociaux, les reproductrices doivent faire face à un dilemme entre coûts et bénéfices de la reproduction asexuée et sexuée. Récemment, il a été montré que les reines termites pouvaient résoudre ce dilemme en optant pour l’utilisation alternée de la reproduction asexuée et sexuée, en produisant des femelles secondaires néoténiques par parthénogenèse, et les ouvriers, soldats et futurs essaimants par reproduction sexuée. Cette stratégie, appelée AQS pour « Asexual Queen Succession », a été décrite chez trois termites souterrains xylophages de la famille des Rhinotermitidae. Deux espèces humivores appartenant à la famille des Termitidae et particulièrement abondantes en forêt néotropicale, Embiratermes neotenicus et Silvestritermes minutus (Syntermitinae), semblaient être des nouvelles candidates pour cette stratégie, car elles présentaient des nids menées par de nombreuses femelles néoténiques. Pour confirmer cette hypothèse et déterminer l’origine génétique de ces femelles, des castes stériles et des futurs essaimants, nous avons développé une banque de microsatellites spécifiques pour E. neotenicus et S. minutus, et génotypé une dizaine de colonies du site de Petit Saut en Guyane, pour chaque espèce. Nous avons confirmé que les castes stériles et les imagos étai ent issus pour la très grande majorité de reproduction sexuée, alors que les femelles néoténiques étaient issues de parthénogenèse avec fusion centrale, un mécanisme différent de celui décrit chez les Rhinotermitidae. La reconstruction détaillée du cycle de vie de S. minutus nous a permis de conclure que l’AQS, au-delà des bénéfices communs à toutes les espèces i.e. la succession de plusieurs générations de reproductrices sans dilution de la participation génétique de la reine fondatrice, l’augmentation du potentiel reproductif de la colonie et la prévention de la consanguinité chez les castes stériles et les imagos, permettait à cette espèce d’investir dans un seul évènement massif d’essaimage pendant un cycle de vie très court. D’autre part, nous avons réalisé une analyse de structuration génétique des colonies et des populations d’E. neotenicus et de S. minutus dans le but de comprendre les conséquences de la dispersion, des modalités d’appariement et de la participation des différents reproducteurs sur la consanguinité des colonies et la potentialité de colonisation de ces espèces. Pour environ 40 colonies de chaque espèce, nous avons montré que les reproducteurs fondateurs étaient très majoritairement non apparentés, et une absence de viscosité à une échelle locale (1 à 11 km), suggérant une dispersion importante des essaimants. De plus, seule une très faible structuration génétique a pu être détectée sur l’ensemble du site d’échantillonnage, indiquant des flux de gènes peu contraints / In social insects, reproductive females have to face a dilemma between costs and advantages of asexual and sexual reproduction. Recently, termite queens were shown to be able to solve this dilemma by using alternatively asexual and sexual reproduction, with the production of secondary neotenic females by parthenogenesis, and workers, soldiers and future alate reproductives by sexual reproduction. This strategy, called AQS for Asexual Queen Succession, was described in three subterranean xylophagous termites of the Rhinotermitidae family. Two soil-feeding species belonging to the Termitidae family, and particularly abundant in Neotropical forest, Embiratermes neotenicus and Silvestritermes minutus (Syntermitinae), seemed to be new candidates for this strategy since they showed colonies headed by numerous neotenic females. In order to confirm this hypothesis and determine the genetic origin of these females, of sterile castes and future imagoes, we developed specific microsatellite libraries for E. neotenicus and S. minutus, and genotyped about ten colonies for each species, on the site of Petit Saut in French Guiana. We confirmed that sterile castes and imagoes were mostly produced by sexual reproduction, while neotenic females were produced by parthenogenesis with central fusion, a mechanism different from that described in Rhinotermitidae species. The detailed reconstruction of S. minutus life cycle allowed us to conclude that AQS, in addition to advantages common to all species i.e. succession of queen generations with undiluted genetic input of the foundress, multiplication of reproductive potential of the colony and prevention of inbreeding in sterile castes and dispersers, would allow this species to optimize a single dispersal event within a very short life cycle. Otherwise, we realized an analysis of colony and population genetic structuration of both species in order to understand consequences of dispersion, mating strategies and parental allocation on inbreeding and colonization abilities of both species. For about 40 colonies of each species, we showed that most of founding reproductives were not related, and absence of genetic viscosity at a local scale (1 to 11 km) suggesting long dispersal flights of alates. Furthermore, only a weak genetic structuration was detected, indicating unfettered gene flows on the sampling site
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Fire Severity and Regeneration Strategy Influence Shrub Patch Size and Structure Following DisturbanceMinor, Jesse, Falk, Donald, Barron-Gafford, Greg 22 June 2017 (has links)
Climate change is increasing the frequency and extent of high-severity disturbance, with potential to alter vegetation community composition and structure in environments sensitive to tipping points between alternative states. Shrub species display a range of characteristics that promote resistance and resilience to disturbance, and which yield differential post-disturbance outcomes. We investigated differences in shrub patch size and stem density in response to variations in fire severity, vegetation community, and post-disturbance reproductive strategies in Sky Island forested ecosystems in the southwestern United States. Patterns in shrub structure reflect the effects of fire severity as well as differences among species with alternate post-fire reproductive strategies. Increased fire severity correlates with larger patch sizes and greater stem densities; these patterns are observed across multiple fire events, indicating that disturbance legacies can persist for decades. High severity fire produces the largest shrub patches, and variance in shrub patch size increases with severity. High severity fire is likely to promote expansion of shrub species on the landscape, with implications for future community structure. Resprouting species have the greatest variability in patch structure, while seeding species show a strong response to disturbance: resprouting species dominateatlowdisturbanceseverities,andobligateseedersdominatehighseverityareas. Differential post-fire reproductive strategies are likely to generate distinct patterns of vegetation distribution following disturbance, with implications for community composition at various scales. Shrub species demonstrate flexible responses to wildfire disturbance severity that are reflected in shrub patch dynamics at small and intermediate scales.
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Táticas reprodutivas e ocorrência parasitária de isópodos em carapeba, Diapterus rhombeus (Cuvier, 1829), no Rio Grande do Norte, Brasil / Reproductive tactics and parasitary occurrence of isopods in carapeba, Diapterus rhombeus (Cuvier, 1829), in Rio Grande do Norte, BrazilFreitas, Maria Daniana Felix de 18 October 2017 (has links)
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Previous issue date: 2017-10-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Diapterus rhombeus is a fish of coastal and estuarine water that can be found throughout the Western Atlantic, from the Gulf of Mexico to Brazil. As it is a peidxe of great abundance it is important to have knowledge about the reproductive and parasitological biology of the species. With this, the objective of this study was to verify the main tactics that compose the reproductive strategy and the condition factor of D. rhombeus and the occurrence of isopod ectoparasites. The study was carried out in marine waters in the Northwest of the Atlantic Ocean (4º 50'57 ''S and 3751'36''W), more precisely in the coast of Areia Branca, RN, Brazil. A total of 298 individuals of the species were captured, in which in the study of their reproductive tactics it was identified that the individuals presented total weight ranges from 51.4g to 220.5g and a total length of 150mm to 245mm, where females were always found to be larger range of total length than males. In the analysis of weight and length both sexes presented a negative allometric growth, that is, the individuals had greater increase in length than in weight. Individuals presented a 1.8M: 1F sex ratio throughout the study. Four stages of gonadal maturation were identified macroscopically: immature, maturing, mature and emptied and microscopic study with histological analysis showed oocyte and sperm development within gonads at each stage of maturation. The length at which individuals entered first maturation was calculated to be 160 mm in total length. The gonadosomatic index (IGS) showed higher peaks for both males and females in November, December and January, indicating that the spawning season occurs soon after this period. The absolute fecundity was 16,313 oocytes and indicated that the females had a synchronous reproductive development in two groups. In the study of condition factor (K) higher peaks were shown shortly after the spawning season, indicating that the greater well-being of the individuals occurs in this period. The parasitic study showed that the species is parasitized by Cymothoa excisa, an isopod parasite that was found inhabiting the oral cavity of the individuals, presenting parasitic indexes with prevalence of 7.38%, mean intensity of 1.18 and average abundance of 0.09. In the present work, D. rhombeus individuals possess reproductive tactics that identify the species as a fish seasonal strategist and that the species can be considered as a new host of the C. excisa isotope ectoparasite / Diapterus rhombeus é um peixe de água costeira e estuarino que pode ser encontrado em todo Oeste do Atlântico, desde o Golfo do México até o Brasil. Como se trata de um peidxe de grande abundancia é importante ter o conhecimento sobre biologia reprodutiva e parasitológica da espécie. Com isso, o objetivo deste estudo foi verificar as principais táticas que compõem a estratégia reprodutiva e o fator de condição de D. rhombeus e a ocorrência de ectoparasitos isópodos. O estudo ocorreu em águas marinhas no Norte do Sudoeste do Oceano Atlântico (4º 50’57’’S e 3751’36’’O), mais precisamente no litoral de Areia Branca, RN, Brasil. Foram capturados 298 indivíduos da espécie, nos quais no estudo das suas táticas reprodutivas foi identificado que os indivíduos apresentaram amplitudes de peso total 51,4g a 220,5g e comprimento total de 150 mm a 245 mm, onde as fêmeas sempre foram encontradas em maior amplitude de comprimento total que os machos. Na análise de peso e comprimento ambos os sexos apresentaram um crescimento alométrico negativo, ou seja, os indivíduos tiveram maior incremento em comprimento que em peso. Os indivíduos apresentaram proporção sexual de 1,8M:1F ao longo do estudo. Quatro estádios de maturação gonadal foram identificados macroscopicamente: imaturos, em maturação, maduros e esvaziados e estudo microscópico com análise histológica mostrou o desenvolvimento ovocitário e espermático dentro das gônadas de cada estágio de maturação. O comprimento em que os indivíduos entraram em primeira maturação foi calculado como sendo em 160mm de comprimento total. O índice gonadossomático (IGS) apresentou picos mais elevados tanto para machos quanto para fêmeas nos meses de novembro, dezembro e janeiro, o que indicou que a época de desova ocorre logo após esse período. A fecundidade absoluta foi de 16.313 ovócitos e indicou que as fêmeas apresentam um desenvolvimento reprodutivo sincrônico em dois grupos. No estudo de fator de condição (K) foi mostrado picos mais elevados logo após a época de desova, indicando que o maior bem-estar dos indivíduos ocorre neste período. O estudo parasitário mostrou que a espécie se encontra parasitada por Cymothoa excisa, parasito isópodo que foi encontrado habitando a cavidade bucal dos indivíduos, apresentando índices parasitários com prevalência de 7,38%, intensidade média de 1,18 e abundancia média de 0,09. Registrando no presente trabalho que os indivíduos da espécie D. rhombeus possuem táticas reprodutivas que identificam a espécie como um peixe estrategista sazonal e que a espécie pode ser considerada como um novo hospedeiro do ectoparasito isópodo C. excisa / 2018-03-28
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Biologia reprodutiva do maracujá brs pérola do cerrado: um estudo de caso com Passiflora setacea DC. Passifloraceae / Reproductive biology of maracujá brs pérola do cerrado: a case study with Passiflora setacea DC. PassifloraceaeTeixeira, Tamara Poliana de Oliveira 23 March 2017 (has links)
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Previous issue date: 2017-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The genus Passiflora includes several wild species that present the potential to be inserted in the market, Passiflora setacea is one of these. Therefore, the study of the reproductive biology of the same was carried out in the Cerrado area of Fazenda Vale do Tamanduá, in the municipality of Aragoiânia in the state of Goiás. In order to analyze the phenology, floral biology, determine the reproductive system, verify visitors And ensure that the flowers undergo predation and whether this fact interferes with the fruiting process. The cultivar blooms year-round, producing fruits with greater intensity in August. Its flowers have characteristics that include it in the chiropteraphilia syndrome, such as white flowers, high nectar production and nocturnal anthesis (18h). The nectar is available only one hour after the anthesis and its production ranged from 135 to 485 microlitres, with a concentration of 18 to 28%. Passiflora setacea is self incompatible, although its self-incompatibility index (0.26)
shows compatibility, this value is very close to the autocompatible species (0.25), so the Kruskal-wallis test showed self-incompatibility for the species. The analysis of the fruits of the self-pollination and cross-treatments revealed that there are significant differences in relation to total weight, pulp yield, seed number, transverse and longitudinal length. In relation to the nocturnal floral visitors, Glossophaga soricina was considered the pollinator due to the presence of pollen grains in its coat and among the daytime floral visitors are bees, wasps, flies and birds. Apis melífera and Trigona spinipes were the most frequent species, presenting pillage behavior, these make illegitimate visits, stealing pollen from the flowers, including pre-anthesis buttons. The birds Eupetonema macroura, Coereba flaviola and the bee Xylocopa grisescens, despite not having frequent visits, were considered to be potential diurnal pollinators due to the fact of making legitimate visits, that is, they contact the reproductive structures during the collection of nectar. The flowers of Passiflora setacea were herbivory mainly by T. spinipes that degrade the hipant of the flower and consequently the nectariferous disk and Icterus jamacaii, that destroys every flower, including the reproductive structures. The results show that although these flowers are damaged, their fruits do not have statistical differences when compared to undamaged flowers / O gênero Passiflora abrange diversas espécies silvestres que apresentam potencial para serem inseridas no mercado, Passiflora setacea é uma destas. Diante disso, o estudo da
biologia reprodutiva da mesma foi realizado em área de Cerrado na Fazenda Vale do Tamanduá, no município de Aragoiânia no estado de Goiás. Objetivando-se analisar a fenologia, a biologia floral, determinar o sistema reprodutivo, verificar os visitantes florais e certificar se as flores sofrem predação e se este fato interfere no processo de frutificação. A cultivar floresce o ano todo, produzindo frutos com maior intensidade em agosto. Suas flores possuem características que a enquadram na síndrome de quiropterofilia, como flores brancas, alta produção de néctar e antese noturna (18h). O néctar encontra-se disponível apenas uma hora após a antese e sua produção variou de 135 a 485 microlitros, com concentração de 18 a 28%. Passiflora setacea é auto incompatível, apesar do seu nível de autoincompatibilidade (0,26) mostrar compatibilidade, este valor está bem próximo para as espécies auto incompatíveis (0,25), sendo assim, análises com o teste Kruskal-Wallis evidenciou autoincompatibilidade para a espécie. A análise dos frutos dos tratamentos de autopolinização e cruzada evidenciam que existe diferenças significativas em relação ao peso total, rendimento da polpa, número de sementes, comprimento transversal e longitudinal. Em relação aos visitantes florais noturnos, Glossophaga soricina foi considerado o polinizador, devido a presença de grãos de polén na sua pelagem e entre os visitantes florais diurnos encontra-se abelhas, vespas, moscas e aves. Apis melífera e Trigona spinipes foram as espécies mais frequentes, apresentando comportamento pilhador, estas fazem visitas ilegítimas, roubando pólen das flores, inclusive de botões em pré-antese. As aves Eupetonema macroura, Coereba flaviola e a abelha Xylocopa grisescens apesar de não ter apresentado visitas frequentes foram consideradas potenciais polinizadores diurnos pelo fato de fazer visitas legitimas, ou seja, contatam as estruturas reprodutivas durante a coleta de néctar. As flores de Passiflora setacea sofreram herbivoria principalmente por T. spinipes que degradam o hipanto da flor e consequentemente o disco nectarífero e Icterus jamacaii, que destrói toda flor, inclusive as estruturas reprodutivas. Os resultados mostram que apesar destas flores serem danificadas, seus frutos não possuem diferenças estatísticas quando comparados com flores não danificadas.
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Size-dependent patterns of reproductive investment in the North American invasive plant species Triadica sebifera (L.) Small (Euphorbiaceae)Babin, Courtney H 19 May 2017 (has links)
Knowledge of sex allocation trade-offs with tree growth in insect-pollinated woody plants is limited, particularly in invasive plants. This study examined patterns of growth and reproductive investment in a North American invasive plant species, Triadica sebifera, I hypothesized that the energy limitations of smaller trees may result in the production of more male reproductive structures that are energetically less costly. Diameter at breast height was a significant predictor of seed and catkin mass and regression can describe these relationships across sites. Seed and catkin mass were positively correlated across sites. The relationship between the seed mass:catkin mass ratio and DBH was not significant, nor was seed mass:catkin mass and total investment. Results showed a significant positive relationship between total reproductive investment and tree size across sites. Seed mass:catkin mass ratio and reproduction investment showed substantial variation among individual trees of similar size within sites.
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The effects of energy quantity to the reproductive strategies of the sea anemone Aiptasia pulchella Carlgren 1943Chen, Chien-Hsun 26 June 2000 (has links)
The effects of energy quantity to the reproductive strategies of the sea anemone Aiptasia pulchella Carlgren 1943
Chien-Hsun Chen
(Advisors: Drs. Keryea Soong, Chao-Lun Chen)
Institute of Marine Biology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan, R.O.C.
Thesis abstract
The influences of energy quantity on the sexual and asexual reproduction and possible trade-offs between them in the sea anemone, Aiptasia pulchella were investigated. Different feeding frequencies, light intensities and presence of zooxanthellae were the treatments of energy quantity. Lacerate numbers, lacerate sizes and total weight of lacerates were used to quantify investment in asexual reproduction; oocyte sizes and gonad weights were used as the measures of sexual reproduction. The correlation between total weight of lacerates and that of gonads provided an opportunity for evidence of trade-offs between sexual and asexual reproduction.
Under higher feeding frequencies, A. pulchella produced more and larger lacerates as well as larger oocytes and heavier gonads than under lower feeding frequencies. Under lower light intensities, A. pulchella produced more and heavier lacerates with than without zooxanthellae. Lacerate sizes were influenced by light intensities, presence of zooxanthellae and the interaction of the two factors. At intermediate light intensity (2000 lux), Aiptasia pulchella produced heavier gonads than at 0 lux or 10000 lux. A. pulchella produced heavier gonads with than without zooxanthellae. The oocyte sizes of A. pulchella were also influenced by light intensities, zooxanthellae and the interaction of the two.
In both sexual or asexual modes of reproduction, A. pulchella performed better under higher than lower feeding frequencies. There were higher level of asexual reproduction for A. pulchella under lower light intensities with zooxanthellae. A. pulchella achieved the highest levels of fecundity, as an indication of sexual reproduction, under a light intensity of 2000 lux in individuals containing zooxanthellae. There is a positive correlation between sexual and asexual investment under different energy regimes. This is not compatible with the prediction of the trade-off hypothesis.
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REPRODUCTIVE BIOLOGY AND FLORAL PHENOLOGY OF SICYOS DEPPEI G. DON (CUCURBITACEAE) IN DISTURBED AREAS IN THE CITY OF SAN ANDRES CHOLULA, PUEBLA, MEXICOVilla-Rodriguez, Sandra 11 February 2013 (has links)
Sicyos deppei G. Don (Cucurbitaceae) is an invasive monoic annual
tendril-bearing vine; it is endemic to Mexico, adapted to the rainfall cycle (June through the end of September) and produces spiny, single seeded fruits. Under serious infestation conditions, S. deppei grows extensively, covering native plants, crops and tree trunks. This study determined the breeding system and pollinators of S. deppei growing in three study sites at urban gardens and disturbed sites at the Campus of the Universidad de las Américas, Puebla in the city of San Andrés Cholula, Puebla (Mexico). Each female inflorescence had an average of 17 flowers at the three study sites. As a step prior to experiments, the timing for stigma receptiveness and pollen viability was determined with the Peroxtesmo KO test (PKO) and Diaminobenzidine test (DAB),respectively. Stigmas of female flowers reach maximum receptivity when flowers are at anthesis; receptivity decreases as the flower reaches the succeeding floral stages. Viability of pollen grains increases with flower development; viabilitypercentages at early stages of floral development are very low, as opposed to the higher percentages of pollen viability found in flowers at anthesis and following developmental stages. Breeding systems were tested for xenogamy and geitonogamy by hand pollinating female flowers. Breeding systems results demonstrated that S. i deppei has a mixed-mating system, being able to set fruit and seed when pollinated with pollen from different plants and from pollen of the same plants. The pollinators were determined with the single-visit method. The diversity of floral visitors in this study was low; the most effective pollinator for S. deppei in this study was Apis mellifera. Throughout the rainy season, this study also described the phenology of S. deppei at the plant and flower level, as well as total plant length. Each stage of development in male and female flowers lasts one day. At the end of the rainy season (N2010) individual plants measured between 947 and 270 cm. / CONACYT, NSERC-CANPOLIN
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Macro and micro-evolutionary processes within a complex of species, case study of the tropical invasive earthworm : pontoscolex corethrurus / Processus macro- et micro-évolutifs au sein d’un complexe d’espèces, cas d’étude de l’espèce tropicale et invasive de vers de terre : pontoscolex corethrurusTaheri, Shabnam 06 March 2018 (has links)
Pontoscolex corethrurus est le ver de terre le plus répandu dans les zones tropicales et sub-tropicales ; il est par conséquent très étudié en science du sol. Il est présent dans toutes sortes d’habitats, des sols pauvres de prairie aux sols riches de forêt primaire, et ses caractéristiques écologiques sont bien connues. Ses caractéristiques biologiques ont été moins étudiées. Peu de données sur la variation génétique au sein de cette morphoespèce sont disponibles à l’exception de la découverte en 2014 de deux lignées génétiquement différentes dans l’île São Miguel des Açores. De plus, son degré de ploïdie n’est pas connu et sa stratégie de reproduction n’est pas bien décrite. L’un des objectifs de cette thèse était de comprendre les mécanismes et les caractéristiques qui font de P. corethrurus un envahisseur efficace. Notre deuxième objectif était de rechercher des lignées cryptiques dans le monde entier et de décrire leurs relations phylogénétiques. Un troisième objectif était d’identifier quelle lignée était invasive et de caractériser la structure génétique de ses populations dans les aires native et d’introduction. Le dernier objectif était de tester si les différentes espèces du complexe avaient différents degrés de ploïdie, ce qui pourrait expliquer l’isolement reproducteur entre ces espèces. Une synthèse bibliographique de 265 études couvrant tous les aspects des connaissances sur P. corethrurus a montré que la stratégie – r et la plasticité de ce ver sont les caractéristiques clefs qui lui permettent d’envahir avec succès différents habitats. Afin d’étudier la diversité cryptique au sein de P. corethrurus à une échelle mondiale, j’ai examiné 792 spécimens collectés dans 25 pays et îles différents. Ces spécimens ont été analysés à l’aide de deux marqueurs mitochondriaux (COI et ADNr 16S), deux marqueurs nucléaires (internal transcribed spacers 2 et ADNr 28S) et une matrice de données de séquence multilocus obtenue à l’aide de la méthode AHE (Anchored Hybrid Enrichment). De plus, un total de 11 caractères morphologiques, internes comme externes, ont été étudiés dans toutes les lignées caractérisées génétiquement. Quatre espèces cryptiques (L1, L2, L3 et L4) ont été observées au sein du complexe d’espèces P. corethrurus. Elles ont été trouvées en sympatrie dans plusieurs localités et des analyses basées sur des marqueurs AFLP n’ont pas montré d’hybridation entre L1 et L3. La possibilité d’isolement reproducteur lié à des degrés de ploïdie différents a été évaluée à l’aide d’expérimentations de cytogénétique pour lesquelles plusieurs obstacles ont été rencontrés, à différentes étapes. Des résultats n’ont été obtenus que pour L4 (2n = 70). L’une des espèces du complexe, L1, était géographiquement répandue. Cette espèce correspondait aux spécimens topotypiques (échantillons provenant du jardin de Fritz Müller où P. corethrurus a été décrit en premier en 1856). Nous avons ciblé cette espèce invasive dans une étude de génétique des populations et de phylogéographie. En utilisant le gène COI et des marqueurs AFLP, nous avons révélé une faible diversité génétique dans la zone tropicale, probablement due à des évènements de colonisation récents et à une reproduction asexuelle. Cependant, la diversité génétique relativement élevée dans certaines populations, associée à un déséquilibre de liaison relativement faible, suggère aussi des évènements de reproduction sexuelle. A ce jour, c’est le premier travail réalisé à l’échelle mondiale sur la diversité génétique cryptique, la génétique des populations et la phylogéographie d’une espèce de vers de terre pérégrine dans la zone tropicale. J’ai produit la première revue complète des caractéristiques de P. corethrurus. De plus, son statut taxinomique a été clarifié ainsi que sa stratégie de reproduction qui est mixte (parthénogénèse et amphimixie). Ces informations seront utiles pour les expérimentations et les recherches futures sur les espèces du complexe P. corethrurus / Pontoscolex corethrurus is the most widespread earthworm species in the tropical and sub-tropical zones, it is hence one of the most studied earthworm in soil science. Ecological aspects of P. corethrurus, which is known to be present in a wide range of habitats from poor soils of pasture to rich soils of primary forest, were intensively investigated but biological aspects are less addressed. In particular, information on the genetic variation within the morphospecies is scarce except for the finding of two genetically differentiated lineages in São Miguel Island of Azores archipelago in 2014. Moreover, the ploidy degree of the morphospecies is not yet known and its reproduction strategy is not well understood. One of the objectives of this thesis was to understand the mechanisms and characteristics which make P. corethrurus a successful invader. Our second objective was to look for cryptic lineages in the whole world and to describe the phylogenetic relationships between them. A third objective was to identify which lineage was invasive and to characterize its population genetic structure in the native and the introduced ranges. The last objective was to test if the different species of the complex have different ploidy degrees (polyploid complex). This could eventually explain the reproductive isolation among these species. A bibliographic synthesis of 265 studies covering all subjects of knowledge on P. corethrurus showed that the r strategy and plasticity of this earthworm are the key characteristics which make it a successful invader in different habitats. In order to investigate the cryptic diversity within P. corethrurus in a world-wide scale, I examined 792 specimens collected from 25 different countries and islands. These specimens were analyzed using two mitochondrial (COI and 16S rDNA) and two nuclear (internal transcribed spacers 2 and 28S rDNA) markers and a large-scale multilocus sequence data matrix obtained using the Anchored Hybrid Enrichment (AHE) method. In addition, a total of 11 morphological characters, both internal and external, were investigated in all genetically characterized lineages. Four cryptic species (L1, L2, L3 and L4) were found within the P. corethrurus species complex, and four potentially new species within the genus Pontoscolex. The cryptic species were observed in sympatry at several localities, and analyses based on AFLP markers showed no hybridization among L1 and L3. The possibility of reproductive isolation among species of the complex because of different ploidy degrees was investigated by cytogenetic experimentations. Due to different obstacles encountered at different steps of the experimentations, results were just obtained for L4 (2n=70). One of the species belonging to the complex, L1, was particularly widespread per comparison with the others. This species corresponded to topotype specimens (samples from Fritz Müller’s garden where P. corethrurus was first described in 1856). Thus, we focused on this invasive species in a population genetics and phylogeography study. Using COI gene and AFLP markers, we revealed low genetic diversity through the tropical zone, probably due to recent colonization events and asexual reproduction type. Meanwhile, due to weak linkage disequilibrium and relatively high genetic diversity in some populations, sexual reproduction was suggested for L1.To date, this is the first study investigating at a world-wide scale, cryptic species diversity, population genetics and phylogeography of a peregrine earthworm species throughout tropical zone. I produced the first comprehensive review of all ecological and biological aspects of P. corethrurus. Moreover, the taxonomic status of P. corethrurus was clarified as well as its reproduction strategy which is mixed (parthenogenetic and sexual). All these findings represent potentially useful information for future experimentations and researches on species of P. corethrurus complex
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Estrat?gia reprodutiva do peixe hermafrodita mussum, Synbranchus marmoratus Osteichthyes, Synbranchidae em um a?ude do Rio Grande do Norte, BrasilBarros, Nirlei Hirachy Costa 27 March 2012 (has links)
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Previous issue date: 2012-03-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Reproductive strategy of the hermaphrodite fish the marbled swamp eel,
Synbranchus marmoratus (Bloch, 1795) (Osteichthyes: Synbranchidae) was
investigated in the Marechal Dutra reservoir, Acari, Rio Grande do Norte, using fish
samples captured monthly during the period of July 2010 to July 2011. The
limnological parameters and rainfall were verified. The captured fish specimens were
numbered, weighed, measured, dissected and their gonads and liver were removed,
weighed and identified as to sex and developmental stages of gonads. The length-weight
relationship was determined for grouped sex. The size of first gonadal maturation,
gonadosomatic index (GSI), condition factor (K) and hepatosomatic index (HSI) were
calculated. The development stages of the gonads were investigated using macroscopic
and histological techniques, besides the fecundity and reproductive period. The
macroscopic characteristics and the histological development of gonads confirmed the
four different sexual types in the sampled population: primary males, females, intersex
and secondary males. The secondary males were bigger and heavier than all the other
types. This species showed a negative allometric growth with a higher increase in length
than weight. The size at which 50% of the females began the process of gonadal
maturation was 43.5 cm of total length, and for secondary males it was 58.5 cm.
Condition factor showed two peaks in February and in April 2011. IGS indicated a
reproductive period from July to September 2010 and was negatively correlated with
the condition factor and rainfall. IGS showed a negative correlation when compared
with the condition factor and the rainy season. HSI was highest in February ad lowest in
December. The reproductive period of this species occurs between the end of the rainy
season and the beginning of the dry season. S. marmoratus presents a seasonal
reproductive strategy which optimizes its reproductive success under the semiarid
climatic conditions / A estrat?gia reprodutiva do peixe hermafrodita mussum, Synbranchus marmoratus
(Bloch, 1795) (Osteichthyes: Synbranchidae) foi investigada no a?ude Marechal Dutra,
Acari, Rio Grande do Norte, utilizando os exemplares capturados mensalmente no
per?odo de julho de 2010 a julho de 2011. Foram verificados os par?metros
limnol?gicos e a pluviosidade. Os exemplares capturados foram numerados, pesados,
medidos, dissecados e o f?gado e as g?nadas foram retiradas, pesadas e identificadas
quanto ao sexo e o est?dio de desenvolvimento gonadal. A rela??o peso-comprimento
foi determinada para sexos agrupados. O tamanho da primeira matura??o, o ?ndice
gonadossom?tico (IGS), o fator de condi??o (K) e o ?ndice hepatossom?tico (IHS)
foram determinados. As fases do desenvolvimento das g?nadas foram investigadas
usando t?cnicas macrosc?picas e histol?gicas, al?m de determinar a fecundidade e o
per?odo reprodutivo da esp?cie. As caracter?sticas macrosc?picas e histol?gicas de
desenvolvimento gonadal confirmaram os quatro tipos sexuais diferentes na popula??o
dos peixes capturados, sendo: machos prim?rios, f?meas, intersexos e machos
secund?rios. Os machos secund?rios apresentaram os maiores valores de comprimento
total e peso total. A esp?cie mostrou um crescimento do tipo alom?trico negativo com
maior incremento em comprimento do que em peso. O tamanho em que 50% da
popula??o das f?meas iniciaram o processo de matura??o gonadal foi de 43,5 cm de
comprimento total e para os machos secund?rios foi de 58,5 cm. O fator de condi??o
apresentou dois picos, um no m?s de fevereiro e outro m?s de abril de 2011. IGS
indicou um per?odo de reprodu??o durante julho a setembro de 2010, mostrando
correla??o negativa ao fator de condi??o. IHS mostrou um pico no m?s de fevereiro
com o menor valor no m?s de dezembro coincidindo com o per?odo de seca da regi?o. A
esp?cie apresenta um per?odo reprodutivo entre o final das chuvas e o in?cio da seca. S.
marmoratus mostra uma estrat?gia reprodutiva sazonal que aperfei?oa seu sucesso
reprodutivo dentro das condi??es clim?ticas do semi?rido.
Palavras chave: mussum, Synbranchus marmoratus, estrat?gia reprodutiva,
hermafroditismo, a?ude do semi?rido
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